Print carrier and transportable cartridge for same

ABSTRACT

A print carrier for use in a chain printer apparatus which comprises an endless band with a plurality of printing fingers integrally formed with the band. Each of the printing fingers is provided with a print character. The band includes at least one integrally formed continuous strip portion, clocking means, and guide means. Desirably, the print carrier is utilized in a transportable cartridge assembly, which includes means for insuring proper print character alignment. The print characters can be made of plastic injection molded onto each of the print fingers.

United States Patent [191 Bowers, Jr. et a1.

PRINT CARRIER AND TRANSPORTABLE CARTRIDGE FOR SAME I Inventors: George W. Bowers, Jr., Hayward;

Tony W. Broski, Jr., San Jose; John Pastrone, Los Gatos, all of Calif.

Assignee: Memorex Corporation, Santa Clara,

Calif.

Filed: Mar. 20, 1970 Appl. No.: 21,464

[52] US. Cl. 101/111, l0l/93 C [51] Int. Cl. B41] 1/20 [58] Field of Search 101/111, 93

[56] References Cited UNITED STATES PATENTS 3,144,821 8/1964 Drejza 101/93 C 3,314,360 4/1967 Foster 101/111 X 3,499,382 3/1970 Potter et a1. 101/93 C 3,605,613 9/1971 DePuy et a1. 101/111 1,371,232 3/1921 Ellis 101/111 2,762,297 9/1956 Baer... 101/93 C [451 Nov. 20, 1973 2,936,704 5/1960 Hense 101/93 C 3,041,964 7/1962 Simpson et a1. 101/111 3,115,092 12/1963 Sasaki 101/111 X 3,216,348 11/1965 Oldenburg et a1. 101/111 X 3,402,657 9/1968 Potter et al. r 101/11 1 X 3,416,442 12/1968 Brown et a1 101/93 C Primary ExaminerEdgar S. Burr Attorney-Limbach, Limbach and Sutton [5 7 ABSTRACT A print carrier for use in a chain printer apparatus which comprises an endless band with a plurality of printing fingers integrally formed with the band. Each of the printing fingers is provided with a print character. The band includes at least one integrally formed continuous strip portion, clocking means, and guide means. Desirably, the print carrier is utilized in a transportable cartridge assembly, which includes means for insuring proper print character alignment. The print characters can be made of plastic injection molded onto each of the print fingers.

8 Claims, 9 Drawing Figures PAIENIEDunvzo 1973 SHEET 1 CF 4 lNvENToRs GEDKGE W. BUM 5K5 ,JK. v

- W BROS/(l BY JOHN PASTKONE ffi fi ATTOKNEV5 TON Y MENTED NOV O 1975 SHEET 2 BF 4 INVENTORS GEOKGE w 50mm 101w w. 520m JK. JOHN PASTKONE ATTO/Z NEYs PRINT CARRIER AND TRANSPORTABLE CARTRIDGE FOR SAME BACKGROUND OF THE INVENTION The present invention relates to a print carrier, and more particularly to a print carrier for use in a chain printing apparatus.

Chain printing apparatus has become important in applications requiring high speed printout. The general operational principle of chain printing is well-known. A chain or print carrier is rotated about two drums or spools. Carried on the chain are a plurality of printing fingers which are each provided with a different print character. Each of the printing fingers will pass past the printing area one time during each revolution of'the chain.

In order to print a character, a hammer assembly is provided within the area about which the print carrier rotates. As the desired character passes the printout area a hammer is actuated. When actuated, the ham-' mer strikes the desired print finger as it passes by which in turn strikes the printout paper.

The speed of printing is largely a function of the speed at which the print carrier can be rotated past the printing area as well as the speed at which the hammers can stroke the print fingers.

Prior art cam'er chain belts include those constructed from woven metallic links and those from rubber belts. In the latter kind, the print characters are placed on pins which are inserted in the edge of the rubber belt. Such constructions are inefficient in operation, expensive to manufacture, and subject to breakage and misalignment at the speeds required in many of todays applications.

Prior art print carriers typically are difiicult to load and unload when a difierent set of characters is required. Further, very few constraints have been placed on the print carrier to insure that the print fingers are properly aligned and positioned at the time when the hammer assembly is activated to print out the desired character.

SUMMARY OF THE INVENTION According to the present invention a continuous print carrier is provided which includes'a plurality of print fingers which are integrally formed with the remainder of the'carrier band or belt. The band or belt additionally includes at least one continuous strip extending circumferentially around the band and also includes timing or clocking means which forms a part of the carrier for co-operative use with suitable sensing means in the chain print apparatus in order to properly actuate the hammer assembly to print the desired character. Desirably, the print fingers are of a bifurcated construction with the print characters secured to the projecting base portion of the bifurcation.

Additionally, guide means are provided on the print carrier which co-operate with the chain printing apparatus to insure that the print fingers are properly aligned in a direction parallel with the axis of rotation of the print carrier. Desirably, the guide means comprises a generally V-shaped projection extending circumferentially around the carrier and may be constructed from an extended plastic sheet bonded to the print carrier or can be formed by crimping a portion of the print carrier itself.

Llt

The print characters can be mounted on each of the plurality of print fingers in a number of ways. For example, the print characters can be made from metal and spot welded toeach of the print fingers. In the preferred embodiment of the present invention, the print characters are made from plastic and are injection molded directly onto the print fingers.

In accordance with yet another feature of the present invention the print carrier band is provided within a transportable cartridge which is adopted for easy placement within a chain printing apparatus. The cartridge includes a recess for receiving the hammer assembly of the chain printing apparatus. The cartridge includes a sidewall portion which cooperates with the guide means on the print carrier band for accurately maintaining the print fingers in the desired position at the time of printing as the print fingers are conveyed past the hammer assembly.

The sidewall additionally includes magnetic guidance means for preventing movement of the print fingers in a radial direction relative to the rotation of the print carrier as the print fingers pass the hammer assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typewriter embodying aspects of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1 along section lines 2-2.

FIG. 3 is a perspective view of a print carrier band in accordance with the present invention.

FIG. 4 is an enlarged view of a portion of the print carrier band shown in FIG. 3.

FIG. 5 is a cross-sectional view of the printcarrier of FIG. 4 shown along the direction indicated by the arrows.

FIG. 6 is a perspective view of another embodiment of the print carrier shown in FIG. 3.

FIG. 7 is a perspective view of an improved print carrier cartridge suitable for use in a chain printing apparatus.

FIG. 8 is a cross-sectional view of the cartridge shown in FIG. 7 in a direction indicated by the arrows.

FIG. 9 is a cross-sectional view of the spool mounting assembly taken along the direction indicated by the arrows in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A general understanding of the chain printing apparatus using the improved print carrier and cartridge of the present invention will be facilitated by reference now to FIGS. 1 and 2. FIG. 2 is a cross-section of FIG. 1 along section lines 2-2. For greater clarity, the sprocket drive for computer type paper is not shown in FIG. 1. The typewriter or other chain printing apparatus is shown on a standard 1 and includes many conventional features including a case 2, a keyboard 4, a cylindrical platen 6 having control knobs 8 at each end, retractable bar'and paper guide rollers 10, fixed paper guide rollers 11, and levers 12 for adjusting to paper thickness and for selecting the number of spaces between lines. Lever 14 controls the release of rollers 16 and 18 and the release of platen 6 in order for paper to be inserted in the machine. A chain printer mechanism or cartridge 20 is mounted adjacent to the face of platen 6 for typing characters on paper between the platen and the printer mechanism. A cross-section of the chain printing apparatus is shown in FIG. 2. A hammer 25 strikes the type character on the chain 22 to drive the character against platen 6 to form an impression.

Two possible paper feeds are shown in FIG. 2. A conventional feed is accomplished by inserting a piece of paper 24 between the rear of platen 6 and retractable rollers 16 and 18. As lever 14 is pulled partially forward, rollers 16 and 18 retract thus facilitating insertion. A second feed, for computer paper is made at opening 26 at the bottom rear of case 2. Paper guides 28 and 30 guide the computer paper 32 along a curved path upward to the platen 6. To permit easy insertion of the computer paper, lever 14 is pulled forward to its extreme position thus moving the entire platen assembly 36 (shown in FIG. 4) to the rear slightly away from vertical spring guide 34. A sprocket drive assembly 38 is employed when using computer paper in the typewriter unit. Details of these two paper feeds are the subject of an application Ser. No. 21,433 filed Mar. 20, 1970 of Ingemar H. Lundquist and John Pastrone filed concurrently herewith.

There is shown in FIG. 3 an improved print carrier chain or belt 101 which is illustrative of the present invention. The belt is rotated about two spools (not shown) located at opposite ends of the belt. The belt is continuous and includes a plurality of print fingers 103 which have included thereon the desired print characters. Located along the bottom of the belt 101 is a clocking means comprising a plurality of perferations or holes 105.

In operation, the belt 101 rotates around spool or drums placed at opposite ends of the print carrier 101 in the direction indicated by the arrow. The exact position of each of the print fingers 103 are easily sensed by any suitable sensing means (not shown) such as a photo or magnetic detector. This information is used to monitor the position of the passing printing fingers and to activate the hammers 25 at the proper time. Thus as the desired print finger 103 passes the hammers 25, the hammer assembly is actuated and a hammer 25 strikes the appropriate print finger 103 to print out the desired character.

A generally V-shaped ridge 109 is provided circumferentially around the print carrier 101. The ridge 109 is utilized in a manner which will be described in more detail subsequently to guide the print fingers 103 past the hammers 25.

Details of the print carrier belt 101 are shown in FIGS. 4 and 5. The print fingers 103 are bifurcated and include a base portion 111 and a pair of legs 113. The ends of the legs 113 are integrally formed with a strip 115 which includes the plurality of timing holes 105. Strip 115 additionally includes a C-shaped hole 117 which acts as the home or reference hole for purposes of monitoring the print fingers 103.

A continuous strip 119 extends circumferentially around the entire print carrier 101. As may be seen, the continuous strip 1 19 is integrally formed with the bifurcated print fingers 103 the legs of which it bisects.

The print carrier 101 can be formed from a single piece of thin material such as stainless steel. It has been found that 410 stainless steel which is magnetic and weldable, and which is approximately 0.005 inches thick works well. The configuration shown in FIG. 3 is desirably formed by use of well-known photo-chemical techniques. However the invention should not be limited thereto since the configuration of FIG. 4 could also be formed by mechanical stamping operations. An endless band is formed by lap-welding or otherwise securing the ends of the band together.

To the base portions 1 11 of the print fingers 103 are attached the desired print characters 121. In the preferred embodiment of the present invention the print characters are made from plastic. The print fingers 103 are placed within a mold having the configuration of the desired character. Plastic such as a polycarbonate is injected within the mold to form the characters 121. Altemately, the characters may be made from metal and spot welded to the print fingers 103.

A guide means formed by the generally V-shaped ridge 109 is best seen by reference to FIG. 5. In the embodiment illustrated in FIGS. 4 and 5, the ridge 109 is made from a material such as polyurethane which is both transparent and flexible. The polyurethane rubber is extruded into a thin band which additionally includes generally flat portions 123 and 125. To secure the extruded ridge 109 and flat portions 123 and 125 to the print carrier 101, a second piece of similar plastic material 127 (FIG. 5) is opposite thereto with the finger portions 113 of the print fingers 103 sandwiched therebetween. The two pieces of plastic are bonded together.

The ridge 109 can be used in conjunction with suitably disposed receiving means provided as a part of the chain print apparatus. Further details of this aspect of the present invention will be described subsequently.

FIG. 6 is illustrative of an alternate means by which the guide means or ridge 109 may be formed. Rather than using extruded plastic bands, the ridge 109 is fonned by crimping the leg portions 113 of the print fingers 103. The legs 113 are crimped into a V-shape suitable for use in guiding the print carrier belt 101. Where practical, other means may be used for guiding the carrier and preventing its movement axially with respect to drive pulleys, but the V-shaped ridge 109 is preferred.

The transportable cartridge 20 shown in FIG. 1 is illustrated in greater detail in FIGS. 7 and 8. The cartridge 20 includes a housing 132 which forms a recess 134 for receiving a hammer assembly 136 illustrated in phantom in FIG. 8. The hammer assembly 136 includes the hammer 25 for striking the print fingers 103 as required. Details of a hammer assembly may be seen by reference to the patent application Ser. No. 21,436 filed Mar. 20, 1970 of Ronald T. Albo and John Pastrone filed concurrently herewith, and assigned to the asignee of the present invention.

The belt 101 rotates within the housing 132 about two spools or drums 138 shown in FIG. 9. The spools 138 are mounted within the housing 132 in an improved manner and will be described subsequently in the description of FIG. 9.

The housing 132 includes a sidewall 140 which includes a recessed portion 142 which cooperates with the V-shaped guide means or ridge 109 of the print carrier 101 as it passes the hammer assembly 136. As a result of this guiding system, the print characters 121 are constrained from moving in a direction parallel with the axis of rotation of the respective spools, e.g., referring to FIG. 8, in an upward or downward direction.

It is also important that the print characters 121 be maintained in a path which is a proper distance from the hammer 25. If the print character 121 is too close to the hammer 25 the print finger 103 can scrape across the surface of the printout paper which can result in damage thereto.

To remedy this problem, an improved magnetic guidance means 146 is provided. Magnetic guidance means 146 includes a strip of magnetic material 148 such as rubber impregnated with magnetized particles which is secured to the sidewall 140 in the vicinity of the hammers 25. The magnetic material is embedded within the sidewall 140 by a [-shaped metal holder 150. In order to prevent damage to the passing print fingers 103, the exposed surface of the magnetic material 148 and the ends of the [-channel 150 are coated with a suitable bearing surface such as Teflon. Thus, as the print fingers 103 pass by the magnetic means 146, the print fingers are drawn to the magnetic material 148 and yet remain undamaged due to the Teflon surface provided thereon. The magnetic guide 146 is particularly effective in holding the print character fingers in line as they come around the pulleys at high speed where centrifugal force tends to pull them out of line. This magnetic guide means 146 is very useful in permitting high speed operation of the chain whether the chain is mounted in the cartridge or directly in the case 2 with the magnetic guide 146 also mounted in the case.

When the cartridge 130 is placed within the chain printing apparatus, the print drive shaft 150 acts against the biasing action of the spring 158 to liftoff the spool 138 from the seat portion 154. In this position, the spool 138 is free to rotate about the bearing 162.

Such a cartridge arrangement gives the chain printing apparatus great flexibility in that different sets of character print can be exchanged easily and conveniently in a very quick and simple operation. Further, as a result of the magnetic guidance means and the guide arrangement used, great accuracy in printout is insured.

We claim:

1. A print carrier for a chain printer apparatus comprising an endless flexible but substantially unstretchable band comprising:

a. an endless central body portion;

b. a continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion rendering said band substantially unstretchable in the circumferential direction;

c. a plurality of printing fingers, each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers projecting from said strip portion at one edge thereof for printing individual characters when struck by a printing hammer;

d. a predetermined plurality of periodic timing indicia in said inelastic strip portion; and

e. guide means formed circumferentially around said central body portion, laterally projecting therefrom for preventing substantially all movement of said band in a direction perpendicular to said circumferential direction.

2. A print carrier as in claim 1 wherein said continuous strip portion and said printing'fingers are formed from a single thin metal strip.

3. A print carrier as in claim 2 wherein said central body portion and said guide means comprise a first flexible plastic belt with a laterally projecting portion on one side, said first belt being disposed on one side of said thin metal strip; and, a second flexible plastic belt oppositely disposed on the other side of said thin metal strip and bonded to said first plastic belt.

4. A print carrier for a chain printer apparatus comprising an endless flexible but substantially unstretchable band comprising;

a. an endless central body portion;

b. a first continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion rendering said band substantially unstretchable in the circumferential direction;

c. a plurality of printing fingers each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and, each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers projecting from said strip portion at one edge thereof for printing individual characters when struck by a printing hammer;

d. a second continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion and including a predetermined plurality of periodic timing indicia located therein; said second strip portion having two connections with each printing finger at the ends of said bifurcated portion of said base; and

e. guide means formed circumferentially around said central body portion, laterally projecting therefrom for preventing substantially all movement of said band in a direction perpendicular to said circumferential direction.

5. A print carrier as in claim 4 wherein said first and second strip portions and said printing fingers are formed from a single thin metal strip. 7

6. The print carrier of claim 5 as characterized further in that said leg portions of said guide means are formed in said metal strip and connected at each end to said metal strip.

7. A print carrier as in claim 5 wherein said central body portion and said guide means comprise a first flexible plastic belt with a laterally projecting portion on one side, said belt being disposed on one side of said thin metal strip, and a second flexible plastic belt oppositely disposed on the other side of said thin metal strip and bonded to said first plastic belt.

8. A print carrier for a chain printer apparatus comprising an endless flexible band having:

a. at least one continuous substantially inelastic metal strip extending in a circumferential direction with said band rendering said band substantially unstretchable in the circumferential direction;

b. a plurality of printing fingers each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and, each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers of leg portions extending around the circumference of said band with the crimped portions projecting laterally from said band for guiding said band in the circumferential direction and preventing substantially all movement of said band in a direction per pendicular to said circumferential direction. 

1. A print carrier for a chain printer apparatus comprising an endless flexible but substantially unstretchable band comprising: a. an endless central body portion; b. a continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion rendering said band substantially unstretchable in the circumferential direction; c. a plurality of printing fingers, each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers projecting from said strip portion at one edge thereof for printing individual characters when struck by a printing hammer; d. a predetermined plurality of periodic timing indicia in said inelastic strip portion; and e. guide means formed circumferentially around said central body portion, laterally projecting therefrom for preventing substantially all movement of said band in a direction perpendicular to said circumferential direction.
 2. A print carrier as in claim 1 wherein said continuous strip portion and said printing fingers are formed from a single thin metal strip.
 3. A print carrier as in claim 2 wherein said central body portion and said guide means comprise a first flexible plastic belt with a laterally projecting portion on one side, said first belt being disposed on one side of said thin metal strip; and, a second flexible plastic belt oppositely disposed on the other side of said thin metal strip and bonded to said first plastic belt.
 4. A print carrier for a chain printer apparatus comprising an endless flexible but substantially unstretchable band comprising; a. an endless central body portion; b. a first continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion rendering said band substantially unstretchable in the circumferential direction; c. a plurality of printing fingers each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and, each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers projecting from said strip portion at one edge thereof for printing individual characters when struck by a printing hammer; d. a second continuous substantially inelastic strip portion extending in a circumferential direction with said central body portion and including a predetermined plurality of periodic timing indicia located therein; said second strip portion having two connections with each printing finger at the ends of said bifurcated portion of said base; and e. guide means formed circumferentially around said central body portion, laterally projecting therefrom for preventing substantially all movement of said band in a direction perpendicular to said circumferential direction.
 5. A print carrier as in claim 4 wherein said first and second strip portions and said printing fingers are formed from a single thin metal strip.
 6. The print carrier of claim 5 as characterized further in that said leg portions of said guide means are formed in said metal strip and connected at each end to said metal strip.
 7. A print carrier as in claim 5 wherein said central body portion and said guide means comprise a first flexible plastic belt with a laterally projecting portion on one side, said belt being disposed on one side of said thin metal strip, and a second flexible plastic belt oppositely disposed on the other side of said thin metal strip and bonded to said first plastic belt.
 8. A print carrier for a chain printer apparatus comprising an endless flexible band having: a. at least one continuous substantially inelastic metal strip extending in a circumferential direction with said band rendering said band substantially unstretchable in the circumferential direction; b. a plurality of printing fingers each printing finger comprising a base with a print character secured to the distal end of said base, said base having a bifurcated portion to provide two points of attachment to said inelastic strip portion, and, each printing finger having two connections with said strip portion, being attached to said strip portion at said bifurcated portion of said base; said printing fingers projecting from said strip portion at one edge thereof for printing individual characters when struck by a printing hammer; c. timing indicia formed in said metal strip; and d. a guide means including a plurality of spaced apart leg portions formed in said metal strip said leg portions each being crimped to form a continuous line of leg portions extending around the circumference of said band with the crimped portions projecting laterally from said band for guiding said band in the circumferential direction and preventing substantially all movement of said band in a direction perpendicular to said circumferential direction. 